Rechargeable batteries used in hand-held battery-powered devices tend to provide power for approximately two hours when fully charged. This greatly limits operating time of the device. Battery and device manufacturers are continually searching for ways for extending battery life, thereby extending device operating time. The following are techniques for getting the most operating time from devices that use rechargeable batteries.
One method is to recharge the rechargeable batteries by removing them from the battery-powered device and inserting them into a recharging stand. Although recharging stands are an effective way for recharging multiple batteries, the recharging stands are quite large and thus take up valuable space and weight in a travel bag if one is to get use from it while traveling.
Tortola et al., U.S. Pat. No. 5,160,879, discloses a rechargeable power pack unit that connects by a cord to a battery-powered device for providing power. The power pack includes a plug that inserts into an AC outlet, thereby receiving AC power that is translated into a DC signal for recharging the rechargeable batteries within the power pack. When the power pack is not connected to an AC outlet and is connected by a jack to a battery-powered device, the rechargeable batteries within the power pack discharge a DC current for powering the device. Essentially, Tortola et al.'s power pack is an additional power source for a battery-powered device, thereby extending operating time of the device. However, this power pack is quite cumbersome. If the battery-powered device is a hand-held game such as a Nintendo.RTM. Gameboy.RTM., the cord and power pack become an inconvenience to the operator who may tend to move the Gameboy.RTM. in an exaggerated fashion in order to operate effectively.